ABSTRACT: Aflatoxin is generated by mycotocins and it is causes a big losses and rasied the managament costs that’s becuase of its extremely high toxicity on unit basis. Research during the last five decades has explored the negative effects of the aflatoxins on health of poultry and sometimes caused disease called Aflatoxciosis. They clamid it has bad effects in both broilers and layers. For example in broilers it is effects on immunity system, performance and gastro intestinal tract and in layers it is caused a decreasing in egg broduction and decreasing in hatching rate. Aflatoxins by effecting the poultry it makes a residue in tissues and organs in diffrent levels and may be caused acute or chronic effects to human health by consuming this tissue and organs and may be has toxcignic, carcinognic proprities that causes complicated issues for human.Key Words: Aflatoxins, aflatoxciosis, broilers, layers, toxicity